So the San Rafael, California, real estate attorney did something purr-fectly nice when drawing up his will: he set aside some $800,000 for cats in need at the Marin Humane Society of Novato, California.

According to the Marin Independent Journal, Kirchoff died after suffering a heart attack last year and left a six-page handwritten will that said "any cash proceeds left shall be donated to the Marin Humane Society for the express benefit and use of their cat fund for the benefit of all the cats which come into their care."

So far the society has received $200,000 and the rest – approximately $600,000 – will arrive before the end of the year, says John Reese, chief operating officer of the organization, who tells PEOPLE that Kirchoff wasn't intimately tied to the organization when he was alive.

Holly Haugh, a former colleague of Kirchoff's, told the Journal that she wasn't surprised when she learned what her friend had done. "He had a passion for cats," she said, adding that the bachelor liked to call himself "Cat Daddy" when talking about his two beloved cats, Chelsea and Tarka (who reside at a Santa Rosa animal sanctuary which received $20,000 to care for them).

The Marin Humane Society hasn't yet determined how they'll use the money, but improvement of their current cat housing could be a future project.

"We will do very generous things for cats with his donation," Reese tells PEOPLE. "It was wonderful for him to consider his cats in the planned giving for his estates and then to also give that donation."